The cost is not just in death from gun violence. There's also the cost of crime (assault, rape, robbery, home invasion) that are deterred by guns. Additionally, you have to look at the deaths you cite and divide them into good deaths and bad death: Criminal killed in the act = good death. The raw statistics neglect that distinction. Killing your attacker also prevents any future crimes that he would have committed. Many criminals are rational opportunists who will ply their trade where they are least likely to be harmed in return by their prey. Case in point: foreign tourists and Florida car rentals. Florida had to eliminate special license plates for rental cars because criminals were targeting them, knowing that the occupants were most likely to be from out of state/country and thus not licensed to carry in Florida. Columbine and Newtown both show that we are very deficient in the area of mental health care for adolescents. The larger question is how to improve that without having government being too intrusive. As a divorcee of several years without a regular job, Nancy Lanza probably had an individual health plan which provided very limited -- often almost worthless -- mental health care options. And how do you get an individual to cooperate when all he's willing to do is stay home & play video games? There are some very difficult policy issues here for legislators, politicians and health authorities to address. Public policy for the last several decades has been not to commit people who are have not been shown to be a danger to themselves or others. There needs to be a middle ground, and there are constitutional obstacles to achieving that middle ground.